Air compressor



Nov. 3o, 1937. L J. MICHAELS 2,100,972

lAIR COMPRESSOR Filed June 9, 1934 f all /7 w f/ l 5; n

Patented Nov. 30, 1937 UNirEo STATES PATENT OFFIQE 1 Claim.

The air compressor embodying this invention is designed for use in establishing a supply of compressed air for air horns, air brakes, inflation of tires, and for other purposes about the vehicle or otherwise.

An object of my invention is to produce a compressor which employs the relative motion which takes place between the vehicle frame and its running gear, as a source of motive power for the operation of the compressor.

A further object is to produce such a compressor as will operate eiiiciently for its full range of operation regardless of its relative degree or percentage of total movement which takes place between the vehicle frame and running gear during normal operation of the vehicle and over roads of usual surface characteristics.

These and other objects are attained in the compressor described in the following specification and illustrated in the accompanying drawing, in which:

Fig. 1 is a sectional elevation of the compressor embodying my invention.

Figs. 2 and 3 are diagrammatic views of a modification of the compressor illustrated in Fig. 1.

Figs. 4 and 5 are diagrammatic views of another modification of the compressor shownr in 3() Fig. 1.

Figs. 6 and 7 are diagrammatic views, similar to Figs. 2 to 5 inclusive, but illustrating an additional modification of the invention I now describe as follows:

A typical compressor embodying my invention has been illustrated in Fig. 1, in which a crank case I has been provided with a mounted casting comprising two cylinders 2a and 2b. Cylinder 2al is the compressor cylinder and contains a piston 40 i6 which is provided with the usual piston rings I'I and is adapted, when reciprocated, to draw in a charge of air around a valve 22 which is reciprocally mounted in a cage 2I and is provided with a light spring 23 held in place by a washer 24 and key 25. A cap 26 closes the valve chamber and the air drawn in by the movementl of the piston enters the cylinder through a port 22a, having passed through a, dirt screen 29 and beneath a shield 36. Upon upward movement of piston I6 the exhaust valve I9 is forced open against the pressure of its spring 20, the valve being guided in its movement by the seat I8. The air thus discharged passes through the union and coupling 21 and 28 into a suitable line or pipe leading to a reservoir or directly to the apparatus to be functioned by the air thus delivered. Illustration of the manner of storage and/or usage of the air has not been made herein because such details do not constitute parts of my invention. l Cylinder 2b has been provided with a pisto 3 which reciprocates therein against a spring 4, a discharge port 5 having been providedto relieve the air pressure in the cylinder and permit of an occasional flushing or lubrication 'when desired. The pistons 3 and IB have been provided with the respective pitmans or connecting rods 6 and I4 which are operated by a rocker arm 8 located in the crank case I of the compressor. Pitman 6 is pivotally mounted on its crank pin I2, the upper end being merely a ball and socket joint relationship with the piston 3. Connecting rod I4 is pivoted at its respective ends on the crank pin I3 and piston pin I5, while the rocker arm is pivoted in the crank case on its pin ID, a boss 9 on the arm forming Ythe bearing forY the pin. Transversely of the arm and parallel to the pins E0, I2 and I3 is another pin I I which mounts a roller "I by means of which the arm is caused to move in an upward direction by means of a cam 34 and in a downward direction when relieved by the cam, through the agency of the spring 4 in cylinder 2b. Cam 34 is keyed or otherwise made a part of a transverse shaft 35 in the crank case so that lwhen it is caused to-reciprocate, it will engage the roller 'I and move it from the position shown to a position in which its face 34a moves counterclockwise and causes roller I to rotate, through which range of movement piston. I5 has been lifted through its entire stroke and is held in the upper limit of its stroke by reason of the fact that cam face 34a is concentric with the axis of rotation of the cam. This means that throughout the angle of movement of the cam, in which the face 34a is in engagement with roller 1, the cam will not cause piston movement. It will also be observed that the piston, because of the peculiarly shaped nose 34h of the cam, will be caused to move rapidly from one limit to the other limit of its stroke. The advantageof this will become obvious` when it is understood that this compressor is designed for operation by virtue of the relative movement between the frame tive vehicle 'part movement, in which the degree of variation has been marked, in` the ordinary use of the vehicle, I have provided a form of linkage which I will now describe.

An arm 38 mounted on cam shaft 35 by means of a washer 35 and a nut 37, is located on the outside of the crank case and is provided at its outer end with a ball 38a which is located between two pads 4i! and 4I within the upper end of a yielding link 43, pad 4I being pressed by spring 42 against ball 38a, while a cap 39 closes the upper end of the link. Since I prefer to mount the compressor on the frame or body portion of the vehicle, I have provided that the lower end of the link 43 be attached to any suitable extension such as arm 49 from the axle or other vibratory part of the vehicle running gear, whereby upward and downward movement of the link will operate arm 38 to create rocker arm movement through the functioning of cam 34. This link 43 has its lower end providedwith a threaded shank 46 which is locked in adjusted position by a nut 45 against the body 43a` of the link, the lower end of the shank having a rounded head which, operating in a correspondingly shaped socket in running gear extension 49,7operates in some such manner as a ball and socket joint. Upon shank 46 a ball Vand socket group 4'! and 48 are reciprocally mounted and are pressed yieldingly by a spring'44 against running gear eXtension 49 so that the link may be free to swing slightly sidewise in any direction relatively to any vertical position and yet be connected with the running gear without any lost motion relatively thereto. Obviously, also, the springs V42 and 44 permit of excess movement of the running gear relatively to the compressor parts so that the cam 34 is held against movement beyond the limits of its motion, such limits being estab-lished by the pad 33 on the bottom of the crank case and by the bearing of the rocker arm 8.

It is obvious that the general principles of my invention may be incorporated in other details of structure such as are suggested in Figs. 2 to 7 inclusive. For example, in Figs. 2 and 3 I have shown diagrammatically, a modiiication in which carn 34 has been displaced by an arm 34o and roller 'l has been displaced by a connected link ia, thereby creating through the agency arm 34e and link 'la a toggle which will cause rocker arm 8 to swing from the position shown in Fig. 2 to that shown in Fig. 3 in which the air in the cylinder has been displaced by the upward movement of the piston I3. Obviously cylinder 2b, spring 4, piston 3, and pitman 6 have been rendered unnecessary in this modified vform of my invention. In substance this modification is practically the same'as that in the preferred form I have described in detail, but the period of complete rest or inoperation of the rocker arm`8, connecting rod i4 and piston i6 which are attained in the form shown in Fig. l, are but approximately obtainable in this modified form of my invention.

In Figs. 4 and 5 I have shown another modification of my invention, in which the presence of the rocker arm 8 has been made unnecessary in that I have merely provided for a direct toggle connection between the compressor arm 33 and the piston I6 by utilizing the connecting rod I4 and having a corresponding toggle connection therewith in the form of an arm 34d as a part of the arm 38 both of which constitute in effect a beli crank in much the same manner that arms 38 and 34o form a bell crank in the form shown in Figs. 2 and 3. In this second modification of my invention cylinder 2bJ spring 4, piston 3 and pitman 6 also have been eliminated.

Further modification of my invention is shown in Figs. 6 and 7 in which I retain the arm 38 and a form of cam 34e which is merely provided with a groove 34f for the roller 1 to operate therein, whereby rocker arm 8 will be forced to be moved downwardly as well as upwardly and without the necessity of the presence of such elements as 2b, 3, 4, and 6. The portion 34g of the cam groove 34j, corresponds to the nose 34h of the cam shown in Fig. 1, and the portion 34h of the groove corresponds to the face 34a of the form of cam shown in Fig. l, the radius of the portion 34h being concentric with the pivot, axis or center of rotation of the'cam 34e whereby roller 'l and arm S will be held against movement in the same mannerthat face 34a. holds the roller 'l arm 8 and piston 56 against movement during vibrations of the running gear in excess of normal amount of movement thereof.

In view of the several forms of embodiment of my invention illustrated herewith, it is obvious that the principle involved is identical in each in that I contemplate utilizing the relative vibratory movement of the running gear with the vehicle frame or body and provide ways and means by which excess of such movement will not create detrimental or undesirable action of the compress-or parts or lead to unnecessary and vdestructive wear and tear thereon. It will be observed that in the simple manner suggested I have obtained a substantial degree of uniformity of operation and a dependable source of motive power by means of which definite and reliable pressures may be built up for the purposes to which such air storage may be employed. It is ob-vious that because of the fact that all the forms of my invention employ a mechanism in which a variable motion 'of the running gear is translated into a substantially nonvariable motion of the compressor parts, the principle I have exemplified is that of obtaining a substantially uniform compression stroke from a variable'power stroke, dimensionally speaking. Equally obvious is it that I have disclosed means for the embodiment of a principle which may be varied along lines other than the principal form which has been shown and described in detail, all without departing from the spirit and scope of the claim which now follows.

I claim:

An air compressor consisting of a casing, a cylinder on the casing, a piston in the cylinder, a rocker arm in the casing, pivotally mounted at one end and pivotally associated with the piston at its opposite end, a cam pivotally mounted in the casing and engaging the rocker arm between the ends thereof, said cam having a portion of its surface adapted to produce arm movement and an adjacent portion adapted to establish arm dwell after a limit of arm movement has been reached, stops limiting the action of said cam to said two portions thereof, and a yielding link connecting the cam with a driving element.

LOUIS J.- MICHAELS. 

